The present disclosure is directed to providing an apparatus and a method to calibrate the operation of an engine. In particular, this disclosure is directed to enabling the operator to calibrate the engine operation, either while the engine is not running or while operating in its intended environment, by changing trim control values, which represent modifications to base engine control values that are based on an engine control map. More particularly, this disclosure is directed to enabling a recreational vehicle rider to generate trim control maps for calibrating base engine control maps, e.g., such as for ignition timing and fuel delivery, while riding or driving the vehicle.
It is believed that the performance of an internal combustion engine is dependent on a number of factors including the operating cycle (e.g., two-stroke, four-stroke, Otto, diesel, or Wankel), the number and design of combustion chambers, the selection and control of ignition and fuel delivery systems, and the ambient conditions in which the engine operates.
Examples of design choices for a combustion chamber are believed to include choosing a compression ratio and choosing the numbers of intake and exhaust valves associated with each chamber. In general, it is believed that these choices cannot be changed so as to calibrate engine operation after the engine has been built.
With regard to ignition systems, breaker point systems and electronic ignition systems are known. It is believed that these known systems provide spark timing based on an operating characteristic of the engine, e.g., speed of rotation and load. In the case of breaker point systems, it is believed that engine speed is frequently detected mechanically using centrifugally displaced weights, and that intake manifold vacuum is commonly used to detect engine load. In the case of electronic ignition systems, it is believed that engine speed is generally detected with an angular motion sensor associated with rotation of the crankshaft, and that engine load is frequently detected, for example, by the output of a throttle position sensor. In each case, spark timing is believed to be fixed according to these known systems for a given operating state of the engine.
With regard to fuel delivery systems, carburetors and fuel injection systems are known. It is believed that these known systems supply a quantity of fuel, e.g., gasoline, that is based on the amount of air being admitted to the engine, i.e., in accordance with the position of the throttle as set by the operator. In the case of carburetors, it is believed that fuel is delivered by a system of orifices, known as xe2x80x9cjets.xe2x80x9d As examples of carburetor operation, it is believed that an idle jet may supply fuel downstream of the throttle valve at engine idling speeds, and that fuel delivery may be boosted by an accelerator pump to facilitate rapid increases in engine speed. It is believed that most carburetors must be disassembled and different size jets or pumps installed to modify the amount of fuel delivery. However, this is a laborious process that, it is believed, that most often, can only be done while the engine is not running.
It is believed that known fuel injection systems, which can be operated electronically, spray a precisely metered amount of fuel into the intake system or directly into the combustion cylinder. The fuel quantity is believed to be determined by a controller based on the state of the engine and a data table known as a xe2x80x9cmapxe2x80x9d or xe2x80x9clook-up table.xe2x80x9d It is believed that the map includes a collection of possible values or xe2x80x9csetpointsxe2x80x9d for each of at least one independent variable (i.e., a characteristic of the state of the engine), which can be measured by a sensor connected to the controller, and a collection of corresponding control values, for a dependent variable control function, e.g., fuel quantity.
Conventionally, it is believed that maps are developed by the engine manufacturer and permanently set in an engine control unit at the factory. Currently, for on-road vehicles, this is believed to be legally required in order to meet emissions regulations. However, it is believed that even when it is not legally required, the manufacturers prevent engine operators from modifying the maps for a variety of reasons such as the manufacturers believe that their maps provide the best engine performance, the manufacturers are afraid that an engine operator might damage the engine by specifying inappropriate control values, or the manufacturers assume that an engine operator might not have sufficient skill to properly modify a map. However, it is believed that the manufacturers have xe2x80x9coptimizedxe2x80x9d their maps to perform best under a set of conditions that they specify. In most cases, it is believed that these conditions do not match the conditions in which the engine is operated. Consequently, stock maps are believed to limit, rather than optimize, an engine""s performance.
It is further believed that ambient conditions such as air temperature, altitude, and barometric pressure affect engine performance. It is believed that these conditions generally impact the entire operating range of the engine. In the case of fuel injection, it is believed to be known to compensation for these conditions by calculating an adjustment for every operating state of the engine.
Thus, engine performance is believed to be substantially dependent on how combustion is accomplished in the ambient conditions. The stoichiometric ratio of air to gasoline is 14.7:1. However, it is believed that ratios from about 10:1 to about 20:1 will combust, and that it is often desirable to adjust the air-fuel ratio to achieve specific engine performance (e.g., a certain level of power output, better fuel economy, or reduced emissions). Similarly, it is also believed to be desirable to adjust ignition timing, commonly measured in degrees of crank rotation before a piston reaches top-dead-center of the compression stroke, to achieve specific engine performance (e.g., lowest fuel consumption or reduced emissions).
It is believed to be a disadvantage of known ignition timing systems and fuel delivery systems that engine operation is constrained by the fixed controls established by the suppliers of these systems. It is also believed to be a disadvantage that any possible adjustments to these known systems requires a technician to reconfigure one or more of the system components, or to disassemble the system, install substitute components, and reassemble the system. Therefore, it is further believed to be a disadvantage of these known systems that neither the effectiveness nor the sufficiency of these adjustments can be determined while continuously operating the engine in its intended environment. And it is yet further believed to be a disadvantage of these known systems that the effect of these adjustments cannot be directly compared.
There is believed to be a need to overcome these disadvantages of known ignition and fuel delivery systems.
The present invention provides a control apparatus for an internal combustion engine that allows an operator to calibrate engine performance relative to an engine operating characteristic. The control apparatus comprises a base engine control map that correlates values of the characteristic with values of a base engine control, a trim control map that correlates the values of the characteristic with values of a trim control, an engine control unit that obtains from the base engine control and trim control maps the respective base engine control and trim control values that are based on the characteristic value, and a panel that is operatively coupled with the engine control unit and includes a first switch regulating a trim signal supplied to the engine control unit. The trim control map is separated from the base control map. The engine control unit calculates an engine operating control value based on the obtained values. The calculated engine operating control value is supplied to the internal combustion engine to vary the engine performance. The first switch is adapted to be manipulated by the operator. And the trim signal causes the engine control unit to modify the trim control values in the trim control map.
The present invention provides another control apparatus for an internal combustion engine that allows an operator to calibrate engine performance. The control apparatus comprises a first sensor detecting a first engine operating characteristic of the internal combustion engine, a second sensor detecting a second engine operating characteristic of the internal combustion engine, a set of base engine control maps correlating values of the first and second characteristics with values of a first base engine control and with values of a second base engine control, a set of trim control maps correlating values of the first and second characteristics with values of a first trim control and with values of a second trim control, an engine control unit that obtains from the sets of base engine control and trim control maps the respective the first base engine control, the second base engine control, the first trim control, and the second trim control values that are based on the first and second characteristic values, a panel operatively coupled with the engine control unit and adapted to interface with the operator, and a display receiving from the engine control unit an information signal. The first sensor supplies a first sensor signal that represents the first characteristic. The second sensor supplies a second sensor signal that represents the second characteristic. The set of trim control maps are separate from the set of base control maps. The engine control unit calculates a first engine operating control value based on the obtained values of the first base engine control and the first trim control, and calculates a second engine operating control value based on the obtained values of the second base engine control and the second trim control. The calculated first and second engine operating control values are supplied to the internal combustion engine to vary the engine performance. The panel includes a first switch and a second switch. The first switch regulates a trim signal supplied to the engine control unit, and is adapted to be manipulated by the operator. The trim signal causes the engine control unit to modify at least one of the first and second trim control values in the set of trim control maps. The second switch regulates a trim defeat signal supplied to the engine control unit, and is adapted to be manipulated by the operator between a first configuration and a second configuration. In the first configuration of the second switch, the trim defeat signal causes the engine control unit to calculate the first and second engine control operating values equal to respective ones of the first and second base engine control values as modify by respective ones of the first and second trim control values. In the second configuration of the second switch, the trim defeat signal causes the engine control unit to calculate the first and second engine control operating values equal to respective ones of the first and second base engine control values. The information signal is indicated by the display so as to be interpretable by the operator.
The present invention provides yet another control apparatus for an internal combustion engine that allows an operator to calibrate engine performance. The control apparatus comprises a first sensor detecting a first engine operating characteristic of the internal combustion engine, a second sensor detecting a second engine operating characteristic of the internal combustion engine, a first set of base engine control maps and a second set of base engine control maps, a first set of trim control maps and a second set of trim control maps, an engine control unit obtains from one of the first and second sets of base engine control and trim control maps respective first base engine control, the second base engine control, the first trim control, and the second trim control values that are based on the characteristic values, a data port operatively coupled to the engine control unit, and a panel operatively coupled with the engine control unit and adapted to interface with the operator. The first sensor supplies a first sensor signal that represents the first characteristic. The second sensor supplies a second sensor signal that represents the second characteristic. Each of the first and second sets of base engine control maps includes a first base engine control map and a second base engine control map. Each of the first base engine control maps correlates values of the first and second characteristics with values of a first base engine control, and each of the second base engine control maps correlates values of the first and second characteristics with values of a second base engine control. The first and second sets of the trim control maps are separate from the first and second sets of the base control maps. Each of the first and second sets of trim control maps includes a first trim control map and a second trim control map. Each of the first trim control maps correlates values of the first and second characteristics with values of a first trim control, and each of the second trim control maps correlates values of the first and second characteristics with values of a second trim control. The engine control unit also calculates a first engine operating control value based on the obtained values of the first base engine control and the first trim control, and calculates a second engine operating control value based on the obtained values of the second base engine control and the second trim control. The calculated first and second engine operating control values are supplied to the internal combustion engine to vary the engine performance. The data port is adapted to download the first and second sets of base control maps from an external processor, and is adapted to upload the first and second sets of the trim control maps to the external processor. The panel includes a first switch that regulates a map selection signal supplied to the engine control unit, a second switch that regulates a trim signal supplied to the engine control unit, and a display receiving from the engine control unit an information signal. The first switch is adapted to be manipulated by the operator between a first arrangement and a second arrangement. In the first arrangement of the first switch, the map selection signal causes the engine control unit to access the first set of base control maps and the first set of trim control maps. In the second arrangement of the first switch, the map selection signal causes the engine control unit to access the second set of base control maps and the second set of trim control maps. The second switch is adapted to be manipulated by the operator. The trim signal causes the engine control unit to modify at least one of the first and second trim control values in the set of trim control maps that are assessed according to the arrangement of the first switch. The information signal is indicated by the display so as to be interpretable by the operator.
The present invention also provides a method for allowing an operator to calibrate engine performance relative to first and second engine operating characteristics of an internal combustion engine. The method comprises providing to an engine control unit a set of base control maps and a set of trim control maps, and modifying with trim signals at least one of the first and second trim control values in a corresponding one of the first and second trim control maps. The set of base control maps includes a first base engine control map and a second base engine control map. The first base engine control map correlates values of the first and second characteristics with values of a first base engine control, and the second base engine control map correlates values of the first and second characteristics with values of a second engine control. The set of trim control maps includes a first trim control map and a second trim control map. The first trim control map correlates values of the first and second characteristics with values of a first trim control, and the second trim control map correlates values of the first and second characteristics with values of a second trim control. The engine control unit obtains from the based engine control and trim control maps respective first base engine control, second base engine control, first trim control, and second trim control values that are based on the characteristic values. The engine control unit also calculates a first engine operating control value based on the obtained values of the first base engine control and the first trim control, and calculates a second engine operating control value based on the obtained values of the second base engine control and the second trim control. The calculated first and second engine operating control values are supplied to the internal combustion engine to vary the engine performance. The trim signals are regulated by a first switch adapted to be manipulated by the operator.